A&p Test 3 - Heart

Front 1

Native depolarization rate of SA node? That is it slowed down by and what is it an example of

Back 1

around 100 bpm

Front 2

What is the native depolarization rate of the SA node slowed down by and what is it an example of?

Back 2

Vagus nerve; Parasympathetic effect

Front 3

The SA node exhibits an _______, "pacemaker potential"

Back 3

Unstable

Front 4

Step 1: Briefly touches against the _________ and then gradually depolarizes ________ through leakage of ______ into the cell (through ____________) without any compensating outflow of ______.

Back 4

Briefly touches against the RESTING POTENTIAL and then gradually depolarizes SPONTANEOUSLY through leakage of NA+ into the cell (through SLOW NA+ CHANNELS) without any compensating outflow of K+.

Front 5

Step 2: At threshold, __________ open and the burst of ________ entering the cell rapidly pushes the cell through ________;

Back 5

At threshold, FAST CA++ CHANNELS open and the burst of CALCIUM entering the cell rapidly pushes the cell through ACTION POTENTIAL

Front 6

Step 3: At peak depolarization, ________ open and _________ rapidly leaves the cell, returning it to ________ briefly until the ____________ open again to initiate slow __________, starting the process over again.

Back 6

At peak depolarization, FAST K+ CHANNELS open and POTASSIUM rapidly leaves the cell, returning it to RESTING POTENTIAL briefly until the SLOW NA+ CHANNELS open again to initiate slow DEPOLARIZATION, starting the process over again.

Front 7

Because the SA node naturally depolarizes the _________, it establishes the normal or "____________" of the heart, with all of the other types of conducting cells "following the leader." If the S.A node is damaged, the next fasting depolarizing member of the conduction system (typically the _____) becomes the "________" and establishes the pace; Is this normal? How does this effect an EKG?

Back 7

Because the SA node naturally depolarizes the FASTEST, it establishes the normal or "SINUS RHYTHM" of the heart, with all of the other types of conducting cells "following the leader." If the S.A node is damaged, the next fasting depolarizing member of the conduction system (typically the AV NODE) becomes the "SECONDARY PACEMAKER" and establishes the pace; This is NOT normal. The EKG looks very different when other conducting tissues establish the pace of the heart.

Front 8

Ventricular systole begins where?

Back 8

At the apex

Front 9

Normal cardiac rhythm is called ________ and is established by the _______ and is ______ bpm at rest.

Back 9

sinus rhythm; SA node; 70-80

Front 10

Know that calcium ions contribute to _________ (the plateau_ as well as in the activity of the ______ and _______; Different from skeletal muscle in which depolarization is solely caused by ________.

Back 10

Know that calcium ions contribute to DEPOLARIZATION (the plateau_ as well as in the activity of the MYOFIBRILS and CONTRACTION; Different from skeletal muscle in which depolarization is solely caused by SODIUM IONS.

Front 11

_______ ions and _______ ions enter cardiac myocytes from what two places?

Back 11

Sodium; Calcium; extracellular space and from adjacent myocytes through gap junctions.

Front 12

Contraction is slower and longer in cardiac/skeletal muscle cells

Back 12

Cardiac

Front 13

The longer ABSOLUTE REFRACTORY PERIOD in cardiac myocytes prevents what two things?

Back 13

Wave summation and Tetany

Front 14

Wave summation and tetany are prevented by what characteristic of cardiac myocytes?

Back 14

A long absolute refractory period.

Front 15

The EKG gives us what kind of information? Give examples.

Back 15

Electrical information; Action potentials: depolarizations and repolarizations

Front 16

The PHYSICAL EVENTS occurring in the heart can be examine by other techniques such as?

Back 16

Echocardiography (sonography of the heart)

Front 17

The physical events of systole and diastole are triggered by?

Back 17

The electrical events that we see in the EKG.

Front 18

Gives us good indications of the electrical activity throughout the heart.

Back 18

EKG